It is by no means irrational to hesitate on a new major release of an Apple operating system. MacOS upgrades have caused many people all kinds of issues, for instance a Big Sur update broke a metric fuckton of USB-C hubs and they didn't address it for 6 months.
I updated from High Sierra to Catalina and it broke a lot of things. Ultimately sold it in the used goods market and switched it for a new laptop. Installed Linux on it and haven't felt the need to go back to Mac since.
